The invention relates to a process for the transportation and accumulation of pallets, having guide rollers and retaining rollers arranged on a traction element on an axle.
Retaining roller chains have been disclosed in German Utility Patent No. 7 728 979, which as a rule are arranged parallel next to each other in two lines whereby support rollers are each time arranged freely rotatable on the bushings of the roller chains. The bolts of the roller chain laterally project on both sides from the chain and carry bearing bushings which ride on correspondingly arranged rail surfaces. The support rollers in turn do not rest on any guide or support surface but are suspended freely rotatable. The chains are generally endless and are driven via suitable driving means. Such retaining roller chains are subject to considerable wear and a uniform and quiet performance cannot be obtained with these chains. When such chains are accelerated or braked, jolts occur which are even more pronounced when the chain is worn. Moreover, a polygonal effect occurs with such retaining roller chain or support chain conveyors during the rotation of the conveyor chain around the drive or guide pulleys which leads to wear thereof. In addition, these roller chains must absorb the weight of the transported object as well as the tractive force so that the wear of such roller chains increases.
Efforts have been made to reduce these problems. In a result of one a house is filled with and emptied of fluid in the horizontal area of such a roller chain so as to not stress the chain with the transported weight since this weight is transmitted via the support rollers to the bearing surfaces and the hose but to only use this arrangement to transmit the tractive force. But the wear near the guides between the advancing and reversing track of such a roller chain continues and, in addition, a device which can be filled with and emptied of fluid must be provided. Also such a roller chain which can be used as a support chain conveyor or as a retaining roller conveyor and in which generally a pair of these roller conveyors next to each other form a roller conveyor requires a frequent lubrication of the chain components. If such roller chains are combined to conveying lengths and retaining roller conveyors as a result of a parallel arrangement, considerable cost regarding the synchronization of the two parallel-running chains cannot be avoided. Because of the occurring wear, an alignment of the support elements with the traction elements is only possible at the expense of additional wear.